The invention generally relates to signatures of the type adapted to be bound into a publication, and more particularly relates to methods of producing such signatures.
In the production of many printed publications, such as books, magazines and the like, signatures are typically created from a moving web of printable material. More specifically, the web is printed, meaning a number of pages are printed across and along the web, with a series of folds then being made in the web to create a multi-layered signature. The web is then cut to release the signature. The edges of the signature are then severed to create individual pages which can be bound together, or which can be combined with one or more signatures to create a larger volume publication.
Conventionally, pages have been printed upon moving webs in a sequential order. However, with the advent of digital printing and print-on-demand machines, the pages of a publication can be formatted and manipulated using a computer screen or other operator interface device prior to actually printing images on the web. Among other things, this allows the operator to select the pages of interest regardless of sequence, and also allows the selected pages to be oriented for proper layout and position when printed onto the web and ultimately folded into a signature.
In addition to being flexible and efficient, it is important that the method by which such signatures are manufactured results in signatures of a sturdy construction which are mechanically compatible with high-speed rotary gathering machines currently used in production of books, magazines, catalogs, directories, etc. A stable signature enables such a high-speed rotary gathering machine to extract a single signature from a stack and place it onto a gathering belt for binding or subsequent combination with other signatures prior to binding.
In accordance with one aspect of the invention, a method of producing a signature is provided which comprises the steps of printing pages onto a moving web, creating multiple fan folds across the web, cutting the web after a desired number of fan folds have been created, and creating at least one chop fold. The web moves along a longitudinal axis with each fan fold being made along a transverse axis of the web, the transverse axis being orthogonal to the longitudinal axis. The cutting step results in a log having a zig-zag configuration in transverse cross-section. Each chop fold is made along the longitudinal axis of the web.
In accordance with another aspect of the invention, a method of producing a bound publication is provided which comprises the steps of traversing a web of printable material along a longitudinal axis, printing pages onto the moving web, fan folding the web transverse to the longitudinal axis, cutting the web transverse to the longitudinal axis resulting in a separated log, chop folding the log along the longitudinal axis to form a signature, shearing edges of the signature to create individual pages, and binding the individual pages together.
In accordance with another aspect of the invention, a signature formed from a moving web of material is provided which comprises a continuous sheet of printable material, at least one fold in the continuous sheet along a transverse axis of the signature, at least one fold in the continuous sheet along a longitudinal axis of the signature and a closed backbone along a first edge of the signature. The moving web has pages printed thereon by a print-on-demand device. The signature is adapted to be gathered and bound by a rotary gathering and binding machine. The continuous sheet has multiple layers wherein each layer has pages printed thereon. The fold along the longitudinal axis creates a fold in the fold made along the transverse axis. The closed backbone is formed by the fold along the longitudinal axis.
These and other features and aspects of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.